Conventionally, abrasive grinding stones and bench grinders are known as sharpeners for sharpening woodworking or household tools by grinding them. Abrasive grinding stones are operated by hand, and the grinding quality varies with the operators and is directly depended upon the skill of the operators. Further, abrasive grinding stones have different materials and grain sizes, which may be not matched with the tools to be grinded. So, abrasive grinding stones are less desired for their tool grinding quality, grinding efficiency and labour consumption.
Two types of bench grinders are available. The first type is called as manual bench grinders. During operation, an operator rotates the bench grinder by his one hand and holds the tool to be grinded by his another hand. It is difficult for the operator to coordinate the actions of his two hands, and thus, the grinding quality can not be ensured. The other type of bench grinder is electric bench grinder, which generally includes a belt driving system. Electric bench grinders are suffered from their complicated structure, bulk size, as well as high vibration and noise created during operation. In addition, known electric bench grinders are not equipped with special clamps and attachments for grinding different tools. During operation, the tool to be grinded is hold by the operator and biased against the grinding stone which is rotated in a high speed, rather than being positioned and clamped by a clamp or attachment. The tool held by hand is likely to move and vibrate, and the grinding angle of the tool is set only by the operator's eyesight. Therefore, the grinding angle and quality can not be ensured. Further, as the grinding stone rotates in a high speed, it requires that the operator paying more attention; otherwise, the grinding quality may be affected and the tool may be damaged.